Air lift dredge



Sept. 29, 1959 F. HEFLING 2,906,040

AIR LIFT DREDGE Original Filed April 21. 1955 2 Sheets-Sheet 1 a 1. 14/ 2? 7 v i 1 20 7 Q I 7 oodcoddo/ooo IN VEN TOR.

Sept. 29, 1959 Original Filed April 21. 1955 F. HEFLING AIR LIFT DREDGE'.

2 Sheets-Shet 2 United States Patent AIR LIFI DREDGE Frank Hefling, Chicago, Ill.

Continuation of application Serial No. 502,928, April 21, 1955. This application June 26, 1958, Serial No. 744,798

4 Claims. (CI. 37-62) This invention relates to dredging apparatus and more particularly to a combination air "lift and dredging apparatus used for excavating and dewatering purposes which can dewater, dredge and jet selectively.

Dredging pipes now available are unable to penetrate relatively hard materials, but are limited to removing soft materials such as silt. Also, the means for lifting materials through the dredge pipe have been expensive and unsuited for use with heavier materials.

It is accordingly an object of the present invention to provide an air lift and dredge for excavating and lifting relatively heavy materials and for dewatering and jetting as desired.

Another object of the invention is to provide an air lift which will form an emulsion of water, air and dredged materials so that the emulsion will be elevated in the pipe with a uniform acceleration.

Another object of the invention is to provide means whereby the pipe can be maneuvered easily into a desired dredging position and which can direct the flow of material from the pipe to a desired location. 7

Another object is to provide a dredge pipe which is simple in construction and may be easily inserted in or removed from the bed of the .body of water being dredged.

Another object is to provide means for jetting relatively uniform bubbles of air into the pipe under a predetermined pressure relative to the static pressure of the water whereby the bubbles in the emulsion thus formed will subdivide at successive points upwardly in the pipe to produce substantially uniform acceleration of the emul- SlOIl.

Another object is to provide dredging means for relatively hard materials combining a cutting edge at the end of the dredge pipe and water jets secured axially around the pipe to cooperate with the cutting edge in penetrating materials.

Other objects and advantages of the invention will become apparent as the description proceeds with reference to the drawings, in which:

Fig; 1 is a side elevational view of air lift and dredging apparatus according to the present invention;

Fig. 2 is an enlarged fragmentary view of the lower end of a dredge pipe according to the invention disclosing an air manifold and water manifold therefor;

Fig. 3 is a horizontal sectional view taken through the air manifold; and

Fig. 4 is a horizontal sectional view taken through the water manifold.

Referring now to Fig. 1, the dredging pipe of the invention may be formed in various lengths and diameters of rigid or flexible sections depending upon the depth of the water and type and volume of material to be dredged.

Various types of discharge units may be secured to the top of pipe 10, to dispose the materials dredged in a desired location. Thus, as seen in Fig. l, a 90 elbow 12 may be used, having a relatively large radius of curvaturein proportion to thediameter. of the pipe 10 to assure ice uninterrupted flow of materials and connected to the pipe 10 by suitable means (not shown). An extension pipe 14 may also be secured axially of the horizontal portion 16 of the elbow 12 if it is desired to dispose the dischargedrmaterial in a location beyond that assured by the size of the elbow 12 and force of ejection resulting from the air lift of the invention. The extension 14 may be of larger diameter than portion 16 of elbow 12, and is secured thereto by means of a bushing (not shown). However, a centrifugal pump 18 may be positioned between elbow 12 and extension 14 to help move the materials through the extension '14. It may also be desirable to provide a discharge vent (not shown) in the pump for use in priming the air lift, which will be located relatively below the portion 16, for effective opera tion. 1

Where a 90 elbow such as the elbow 12 is utilized, and where feasible with other discharge units of the pipe, a perforate bracket 20, often referred to as a cockscomb, is welded or otherwise secured in upright position to the elbow along the upper surface of the elbow and preferably along the curve thereof, the apertures extending horizontally to accommodate the rigging. The bracket or cockscomb '20 thus permits the pipe 10 to be maneuvered to avoid obstacles by adjusting the-pitch or angleof the pipe.

Other types or discharge units may also be secured to the top of the pipe 10 to fit a particular need.

Referring now to Fig. 1, the lower end of the pipe 10 is provided with an air manifold 22 and a water manifold 24 for purposes to be hereinafter described. I The air manifold 22 maybe supplied through a conduit 26 secured axially along the-pipe 10 by bracketsor the like and providing a variable pressure by means of a suitable. air valve (not shown). The water manifold 24 may be supplied through a conduit '28 likewise controlled through a valve 30 to produce'a suitable pressure. p The bottom end of the pipe 10 is provided with an annular and preferably integrally formed cutting edge 32 adapted to penetrate and to loosen relatively hard materials, as seen in Fig. 2. A sieve 34 may be provided if desired to prevent materials of an undesirable size from clogging the pipe. Referring now to Fig. 2, the air manifold 22 and water manifold 24 have a rounded configuration and may be secured to the main body of the pipe 12 by welding or other suitable means. This construction for the mani folds permits the pipe to be moved easily without getting fouled. At the same time, an even or uneven pressure of air and water respectively is provided by the manifolds 2'2 and 24. Jet tubes or pipes 36 are set in the pipe 10 at sub stantially at 6 angle from the vertical, and spaced, from each other at preferably equal distances, around the pipe at a predetermined distance from the bottom end thereof. The rounded construction of the manifold 22 deflects the air upwardly into the air jets 36 after it enters through conduit 26 at the top of the manifold, the ends 38 of the pipes 36 being spaced a predetermined distance from the lower juncture 40 between the manifold and pipe 10. The air is introduced into the manifold 22 at a pressure having a definite relationship to the static pressure of the water at the same level. Preferably this pressure is substantially fifteen pounds more than. the static pressure of the water at the level of the manifold 22 although variations from this preferred pressure may acceleration due to the expansion and increased; displace:

ment developed by the air as it moves higher and higher in the pipe.

The air jets 36 have bores which are non-tapering and of substantially uniform diameter, so that the air in manifold 22 will be injected evenly into the pipe to form air bubbles of a fairly uniform size in the emulsion. However, it will be appreciated that by calculating the total cross-sectional area of the pipes 36- at less than the cross-sectional area of conduit 26, an increased jetting action will be afforded, if desired, and vice versa.

A suflicient number of air jets must be provided to insure that the distribution of air bubbles across the pipe will be even, so that the lifting action will be steady and sustained. Thus, at least two such jets will be required for uniform distribution of air, and in the embodiment shown in the drawings, eight are employed.

Also, the air jets 36 are disposed slightly upwardly of cutting edge 32 a predetermined distance so that water and dredged materials will be drawn upwardly with a strong and steady pull by the lift created through the elevation of the emulsion formed by the said jets.

As the emulsion rises in the pipe 10 and as the pressure decreases accordingly, the air bubbles suspended therein will successively subdivide at regular intervals to maintain the constant acceleration of the emulsion.

The water manifold 24 is also spaced a predetermined distance from the cutting edge 32 and below manifold 22, and as seen in Figs. 2 and 4 a plurality of water pipes or jets 42 are secured in the manifold 24 preferably by welding, along the pipe 10 and in axial relation thereto. The jets 42 are spaced evenly from each other around the pipe 10, and while the number of such jets may vary with the diameter of the pipe 10, normally at least two are required to cooperate with cutting edge 32 in dredging relatively hard materials. The water pressure necessary to produce an effective dredging action may be obtained by means of valve 30, as stated.

Although it has been found that air is very satisfactory in lifting the emulsion, other gases such as, for example, nitrogen or hydrogen, may also be employed within the scope of the invention.

Applicant has accordingly provided an air lift and dredge which will penetrate relatively hard materials and elevate them efficiently, and which may be used in a wide variety of excavating and dewatering jobs.

Although one specific structure for the improved air lift dredging apparatus has been described herein, and although the cutting edge of the dredging pipe and water jets adapted to cooperate therewith have been illustrated in a specific embodiment, it will be understood that numerous details of the construction shown may be altered or omitted without departing from the spirit of this invention as defined by the following claims.

This application is a continuation of application Serial No. 502,928 filed April 21, 1955 for Air Lift Dredge and now abandoned.

I claim:

1. In a dredging apparatus, a depending dredge pipe for use below water having a substantially internally smooth open lower end terminating in a cutting edge, a plurality of downwardly opening water jet nozzles spaced peripherally around said lower end above the cutting edge to cooperate therewith in directing streams of water downwardly in a cutting circle to penetrate and loosen materials of variable density, means for supplying water under pressure to said water jets including a jacket around the inlets of said water jets, a plurality of air jet nozzles spaced around said pipe a predetermined distance above the lower end thereof and projecting essentially upwardly from the inside wall of the pipe, means for supplying air to said air jet nozzles under pressure including a second jacket around the inlet ends of said air jet nozzles to generate and lift an amulsion of air, water and dredged materials in said pipe, and means for withdrawing said emulsion from the top of said pipe.

2. In a dredging apparatus, a depending dredge pipe, means for directing water downwardly in a cutting circle around said dredging end of-said pipe, a cutting edge on said dredging end of said pipe adapted to cooperate with said water-ejecting means to penetrate and loosen materials of variable density, a plurality of upwardly directed air jet nozzles peripherally spaced around and inside the pipe a predetermined distance above the cutting edge, means separate from the water directing means for supplying air to said jet nozzles under predetermined pressure, an elbow discharge unit having one leg disposed axially to said dredging pipe and the other substantially horizontally thereto, the bend portion of the elbow discharge unit having a relatively large radius of curvature in proportion to the diameter of said dredging pipe for unobstructed flow of materials therethrough, and a support bracket secured along said elbow at substantially the top end thereof and having a plurality of horizontally spaced apertures along the top thereof to afford selective depending angular adjustment of the depending dredge pipe when the bracket is supported in inclined positions at predetermined ones of said apertures.

3. In a dredging apparatus, a depending dredge pipe for use below water having a substantially internally smooth open lower end terminating in a cutting edge, a plurality of downwardly opening water jet nozzles spaced peripherally around and contiguous with the outer surface of said lower end above the cutting edge to cooperate therewith in directing streams of water downwardly in a cutting circle to wash said cutting edge and penetrate and loosen materials of variable density, means for supplying water under pressure to said Water jets including a jacket around the inlets of said water jets, a plurality of air jet nozzles peripherally spaced around the pipe and extending through the wall of the pipe in predetermined spaced relation above the lower end thereof with the outlets of the nozzles exposed inside said pipe and pointed essentially upwardly along the inside wall of said pipe, means for supplying air to said air jet nozzles under pressure including a second jacket around the inlet ends of said air jet nozzles to generate and lift an emulsion of air, water and dredged materials in said pipe, an elbow discharge unit having one leg disposed axially to said dredging pipe and the other substantially horizontally thereto, the bend portion of the elbow discharge unit having a relatively large radius of curvature in proportion to the diameter of said dredging pipe for unobstructed flow of materials therethrough, and means carried by said elbow for supporting said depending dredge pipe in any one of a plurality of selective angularly depending adjusted inclined positions including a plurality of horizontally spaced fastening elements for relative support at any one of a number of positions.

4. In a dredging apparatus, a depending dredge pipe for use below water having an open lower end terminating in a cutting edge, a plurality of downwardly opening water jet nozzles externally spaced peripherally around said lower end above the cutting edge to cooperate therewith in directing jets of Water downwardly along the cutting edge in a cutting circle to penetrate and loosen materials of variable density, means for supplying water under pressure to said water jets including a jacket around the inlets of said water jets, a plurality of air jet nozzles peripherally spaced around the pipe and extending through the wall of the pipe in predetermined spaced relation above the lower end thereof with the outlets of the nozzles exposed inside said pipe and pointed essentially upwardly from and along the inside wall of said pipe, means for supplying air to said air jet nozzles under pressure including a second jacket around the inlet ends of said air jet nozzles to generate and lift an emulsion of air, water and dredged materials in said pipe, an elbow discharge unit having one leg disposed axially to said dredging pipe and the other substantially horizontally thereto, the bend portion of the elbow discharge unit having a relatively large radius of drawing said emulsion from said elbow discharge unit, said emulsion of air and water in said pipe levitating to prime and maintain said pump primed during its operation.

No references cited. 

